<?php

namespace GetId3\Module\Audio;

use GetId3\Handler\BaseHandler;
use GetId3\Lib\Helper;
use GetId3\GetId3Core;
use GetId3\Module\Tag\Id3v2;

/////////////////////////////////////////////////////////////////
/// GetId3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.audio.la.php                                         //
// module for analyzing BONK audio files                       //
// dependencies: module.tag.id3v2.php (optional)               //
//                                                            ///
/////////////////////////////////////////////////////////////////

/**
 * module for analyzing BONK audio files
 *
 * @author James Heinrich <info@getid3.org>
 *
 * @link http://getid3.sourceforge.net
 * @link http://www.getid3.org
 */
class Bonk extends BaseHandler
{
    /**
     * @return bool
     */
    public function analyze()
    {
        $info = &$this->getid3->info;

        // shortcut
        $info['bonk'] = array();
        $thisfile_bonk = &$info['bonk'];

        $thisfile_bonk['dataoffset'] = $info['avdataoffset'];
        $thisfile_bonk['dataend'] = $info['avdataend'];

        if (!Helper::intValueSupported($thisfile_bonk['dataend'])) {
            $info['warning'][] = 'Unable to parse BONK file from end (v0.6+ preferred method) because PHP filesystem functions only support up to '.round(PHP_INT_MAX / 1073741824).'GB';
        } else {

            // scan-from-end method, for v0.6 and higher
            fseek($this->getid3->fp, $thisfile_bonk['dataend'] - 8, SEEK_SET);
            $PossibleBonkTag = fread($this->getid3->fp, 8);
            while ($this->BonkIsValidTagName(substr($PossibleBonkTag, 4, 4), true)) {
                $BonkTagSize = Helper::LittleEndian2Int(substr($PossibleBonkTag, 0, 4));
                fseek($this->getid3->fp, 0 - $BonkTagSize, SEEK_CUR);
                $BonkTagOffset = ftell($this->getid3->fp);
                $TagHeaderTest = fread($this->getid3->fp, 5);
                if (($TagHeaderTest{0} != "\x00") || (substr($PossibleBonkTag, 4, 4) != strtolower(substr($PossibleBonkTag, 4, 4)))) {
                    $info['error'][] = 'Expecting "'.Helper::PrintHexBytes("\x00".strtoupper(substr($PossibleBonkTag, 4, 4))).'" at offset '.$BonkTagOffset.', found "'.Helper::PrintHexBytes($TagHeaderTest).'"';

                    return false;
                }
                $BonkTagName = substr($TagHeaderTest, 1, 4);

                $thisfile_bonk[$BonkTagName]['size'] = $BonkTagSize;
                $thisfile_bonk[$BonkTagName]['offset'] = $BonkTagOffset;
                $this->HandleBonkTags($BonkTagName);
                $NextTagEndOffset = $BonkTagOffset - 8;
                if ($NextTagEndOffset < $thisfile_bonk['dataoffset']) {
                    if (empty($info['audio']['encoder'])) {
                        $info['audio']['encoder'] = 'Extended BONK v0.9+';
                    }

                    return true;
                }
                fseek($this->getid3->fp, $NextTagEndOffset, SEEK_SET);
                $PossibleBonkTag = fread($this->getid3->fp, 8);
            }
        }

        // seek-from-beginning method for v0.4 and v0.5
        if (empty($thisfile_bonk['BONK'])) {
            fseek($this->getid3->fp, $thisfile_bonk['dataoffset'], SEEK_SET);
            do {
                $TagHeaderTest = fread($this->getid3->fp, 5);
                switch ($TagHeaderTest) {
                    case "\x00".'BONK':
                        if (empty($info['audio']['encoder'])) {
                            $info['audio']['encoder'] = 'BONK v0.4';
                        }
                        break;

                    case "\x00".'INFO':
                        $info['audio']['encoder'] = 'Extended BONK v0.5';
                        break;

                    default:
                        break 2;
                }
                $BonkTagName = substr($TagHeaderTest, 1, 4);
                $thisfile_bonk[$BonkTagName]['size'] = $thisfile_bonk['dataend'] - $thisfile_bonk['dataoffset'];
                $thisfile_bonk[$BonkTagName]['offset'] = $thisfile_bonk['dataoffset'];
                $this->HandleBonkTags($BonkTagName);
            } while (true);
        }

        // parse META block for v0.6 - v0.8
        if (empty($thisfile_bonk['INFO']) && isset($thisfile_bonk['META']['tags']['info'])) {
            fseek($this->getid3->fp, $thisfile_bonk['META']['tags']['info'], SEEK_SET);
            $TagHeaderTest = fread($this->getid3->fp, 5);
            if ($TagHeaderTest == "\x00".'INFO') {
                $info['audio']['encoder'] = 'Extended BONK v0.6 - v0.8';

                $BonkTagName = substr($TagHeaderTest, 1, 4);
                $thisfile_bonk[$BonkTagName]['size'] = $thisfile_bonk['dataend'] - $thisfile_bonk['dataoffset'];
                $thisfile_bonk[$BonkTagName]['offset'] = $thisfile_bonk['dataoffset'];
                $this->HandleBonkTags($BonkTagName);
            }
        }

        if (empty($info['audio']['encoder'])) {
            $info['audio']['encoder'] = 'Extended BONK v0.9+';
        }
        if (empty($thisfile_bonk['BONK'])) {
            unset($info['bonk']);
        }

        return true;
    }

    /**
     * @param type $BonkTagName
     */
    public function HandleBonkTags($BonkTagName)
    {
        $info = &$this->getid3->info;
        switch ($BonkTagName) {
            case 'BONK':
                // shortcut
                $thisfile_bonk_BONK = &$info['bonk']['BONK'];

                $BonkData = "\x00".'BONK'.fread($this->getid3->fp, 17);
                $thisfile_bonk_BONK['version'] = Helper::LittleEndian2Int(substr($BonkData, 5, 1));
                $thisfile_bonk_BONK['number_samples'] = Helper::LittleEndian2Int(substr($BonkData, 6, 4));
                $thisfile_bonk_BONK['sample_rate'] = Helper::LittleEndian2Int(substr($BonkData, 10, 4));

                $thisfile_bonk_BONK['channels'] = Helper::LittleEndian2Int(substr($BonkData, 14, 1));
                $thisfile_bonk_BONK['lossless'] = (bool) Helper::LittleEndian2Int(substr($BonkData, 15, 1));
                $thisfile_bonk_BONK['joint_stereo'] = (bool) Helper::LittleEndian2Int(substr($BonkData, 16, 1));
                $thisfile_bonk_BONK['number_taps'] = Helper::LittleEndian2Int(substr($BonkData, 17, 2));
                $thisfile_bonk_BONK['downsampling_ratio'] = Helper::LittleEndian2Int(substr($BonkData, 19, 1));
                $thisfile_bonk_BONK['samples_per_packet'] = Helper::LittleEndian2Int(substr($BonkData, 20, 2));

                $info['avdataoffset'] = $thisfile_bonk_BONK['offset'] + 5 + 17;
                $info['avdataend'] = $thisfile_bonk_BONK['offset'] + $thisfile_bonk_BONK['size'];

                $info['fileformat'] = 'bonk';
                $info['audio']['dataformat'] = 'bonk';
                $info['audio']['bitrate_mode'] = 'vbr'; // assumed
                $info['audio']['channels'] = $thisfile_bonk_BONK['channels'];
                $info['audio']['sample_rate'] = $thisfile_bonk_BONK['sample_rate'];
                $info['audio']['channelmode'] = ($thisfile_bonk_BONK['joint_stereo'] ? 'joint stereo' : 'stereo');
                $info['audio']['lossless'] = $thisfile_bonk_BONK['lossless'];
                $info['audio']['codec'] = 'bonk';

                $info['playtime_seconds'] = $thisfile_bonk_BONK['number_samples'] / ($thisfile_bonk_BONK['sample_rate'] * $thisfile_bonk_BONK['channels']);
                if ($info['playtime_seconds'] > 0) {
                    $info['audio']['bitrate'] = (($info['bonk']['dataend'] - $info['bonk']['dataoffset']) * 8) / $info['playtime_seconds'];
                }
                break;

            case 'INFO':
                // shortcut
                $thisfile_bonk_INFO = &$info['bonk']['INFO'];

                $thisfile_bonk_INFO['version'] = Helper::LittleEndian2Int(fread($this->getid3->fp, 1));
                $thisfile_bonk_INFO['entries_count'] = 0;
                $NextInfoDataPair = fread($this->getid3->fp, 5);
                if (!$this->BonkIsValidTagName(substr($NextInfoDataPair, 1, 4))) {
                    while (!feof($this->getid3->fp)) {
                        //$CurrentSeekInfo['offset']  = GetId3_lib::LittleEndian2Int(substr($NextInfoDataPair, 0, 4));
                        //$CurrentSeekInfo['nextbit'] = GetId3_lib::LittleEndian2Int(substr($NextInfoDataPair, 4, 1));
                        //$thisfile_bonk_INFO[] = $CurrentSeekInfo;

                        $NextInfoDataPair = fread($this->getid3->fp, 5);
                        if ($this->BonkIsValidTagName(substr($NextInfoDataPair, 1, 4))) {
                            fseek($this->getid3->fp, -5, SEEK_CUR);
                            break;
                        }
                        ++$thisfile_bonk_INFO['entries_count'];
                    }
                }
                break;

            case 'META':
                $BonkData = "\x00".'META'.fread($this->getid3->fp, $info['bonk']['META']['size'] - 5);
                $info['bonk']['META']['version'] = Helper::LittleEndian2Int(substr($BonkData, 5, 1));

                $MetaTagEntries = floor(((strlen($BonkData) - 8) - 6) / 8); // BonkData - xxxxmeta - ØMETA
                $offset = 6;
                for ($i = 0; $i < $MetaTagEntries; ++$i) {
                    $MetaEntryTagName = substr($BonkData, $offset, 4);
                    $offset += 4;
                    $MetaEntryTagOffset = Helper::LittleEndian2Int(substr($BonkData, $offset, 4));
                    $offset += 4;
                    $info['bonk']['META']['tags'][$MetaEntryTagName] = $MetaEntryTagOffset;
                }
                break;

            case ' ID3':
                $info['audio']['encoder'] = 'Extended BONK v0.9+';

                // ID3v2 checking is optional
                if (class_exists('GetId3\\Module\\Tag\\Id3v2')) {
                    $getid3_temp = new GetId3Core();
                    $getid3_temp->openfile($this->getid3->filename);
                    $getid3_id3v2 = new Id3v2($getid3_temp);
                    $getid3_id3v2->StartingOffset = $info['bonk'][' ID3']['offset'] + 2;
                    $info['bonk'][' ID3']['valid'] = $getid3_id3v2->analyze();
                    if ($info['bonk'][' ID3']['valid']) {
                        $info['id3v2'] = $getid3_temp->info['id3v2'];
                    }
                    unset($getid3_temp, $getid3_id3v2);
                }
                break;

            default:
                $info['warning'][] = 'Unexpected Bonk tag "'.$BonkTagName.'" at offset '.$info['bonk'][$BonkTagName]['offset'];
                break;

        }
    }

    /**
     * @staticvar array $BonkIsValidTagName
     *
     * @param  type    $PossibleBonkTag
     * @param  type    $ignorecase
     *
     * @return bool
     */
    public static function BonkIsValidTagName($PossibleBonkTag, $ignorecase = false)
    {
        static $BonkIsValidTagName = array('BONK', 'INFO', ' ID3', 'META');
        foreach ($BonkIsValidTagName as $validtagname) {
            if ($validtagname == $PossibleBonkTag) {
                return true;
            } elseif ($ignorecase && (strtolower($validtagname) == strtolower($PossibleBonkTag))) {
                return true;
            }
        }

        return false;
    }
}
